Osprey

license

Apache-2.0(OSI)

source

public

self-host

yes

service

none

core-gated

ungated

Fully open source: Apache-2.0 real-time safety rules engine, self-hostable, no proprietary tier. Donated by Discord to ROOST.

• https://github.com/roostorg/osprey recorded 2026-08-13

  Repo metadata records license spdxId - Apache-2.0. README brings the full stack up with one Docker Compose command (./demo.sh) and describes it as 'a working system, not a prototype', pointing at the development guide for building it yourself; ROOST is a non-profit and there is no paid tier, enterprise directory or license key on the page.

Community breadth is modest, but Osprey runs in production at marquee platforms, and that is what the band rests on. The repo itself carries none of it: the 'Adopters' list is empty and no throughput figure appears there. ROOST's v1.0 announcement is where the evidence sits - it says Osprey 'processes over 50M events daily in production environments like Bluesky' and carries quotes from Discord, Bluesky and Matrix confirming the named deployments. No numeric reach is recorded, because a named-deployment claim of this kind carries a word rather than a count.

• https://roost.tools/blog/introducing-osprey-v1-0-open-source-infrastructure-for-real-time-abuse-mitigation/ recorded 2026-08-13

  V1.0 announcement, published January 28, 2026. Osprey 'processes over 50M events daily in production environments like Bluesky and is designed for real-time incident response'. Named production users with attributed quotes - Discord (Savannah Badalich, Global Head of Product Policy), Bluesky (Aaron Rodericks, Head of Trust and Safety) and The Matrix.org Foundation (Jim Mackenzie, VP of Trust & Safety). No download, install or customer count is published.

• https://github.com/roostorg/osprey recorded 2026-08-13

  stargazerCount 462 for roostorg/osprey. The README's 'Adopters' section reads 'Osprey is used by:' with nothing under it.

Battle-tested at Discord scale, but a single-purpose Trust and Safety rules engine rather than an AI-native guardrail. The only published throughput figure is ROOST's v1.0 announcement, which says Osprey "processes over 50M events daily in production environments like Bluesky"; the larger numbers sometimes attributed to it - around 2.3M rules/sec and 400M daily actions at Discord - appear on none of the sources cited here and nowhere in the README. The engine itself is "a safety rules engine and investigation console for real-time event processing at scale", with rules "written in SML, Osprey's structured rule language, and extended with user-defined functions (UDFs)", built at Discord. Running at that scale earns the 4; being single-purpose is why it is not an AI-native guardrail.

• https://github.com/roostorg/osprey recorded 2026-08-13

  README describes 'a safety rules engine and investigation console for real-time event processing at scale' where 'human-written rules evaluate each one as it arrives', with rules 'written in SML, Osprey's structured rule language, and extended with user-defined functions (UDFs)', originally built at Discord. It carries no throughput figures and no longer describes the Rust/Python worker split.

• https://roost.tools/blog/introducing-osprey-v1-0-open-source-infrastructure-for-real-time-abuse-mitigation/ recorded 2026-08-14

  The published throughput figure that replaces the vanished ones - Osprey "processes over 50M events daily in production environments like Bluesky and is designed for real-time incident response".

• https://github.com/roostorg/osprey recorded 2026-08-14

  The README carries no occurrence of "2.3M" or "400M" anywhere, so the figures the recorded value led with are not recoverable from it. What it does still carry is the engine the band rests on - "a safety rules engine and investigation console for real-time event processing at scale", rules written in SML and extended with user-defined functions.